Fabrication of High Aspect RatioMEMS Devices for DoD Applications

using Hot Embossing Technology

William BenardMEMS Exchange

www.mems-exchange.org

Tank-automotive & Armaments COMmand

Safing and Arming Device

Safing and Arming Device

www.mems-exchange.org

• LIGA high-aspect-ratio MEMS fabrication

• 10-mm x 10-mm substrate dies

• About 36 dies fit on a 4” wafer

LIGA (nickel) micro-parts are micro-assembled intoLIGA-formed“frames”

‘Frame’ die

Safing and Arming Device

Flight Test Data

• 300-m range to target

• 490 RPS spin

• Soft Catch (fiberboard)

• Rounds recovered

• All S&As armed

Recovered Assembly

Armed S&A!

Mann Barreland Target

Currently being Transitioned to Production

Safing and Arming Device

www.mems-exchange.org

Problems:•Cost - parts to be made in high volume with aggressive price goals.•Assembly – tolerances are tight and parts are awkward to handle.

Solution:•Alternative fabrication, hot embossing offers several avenues for reducingfabrication and possibly assembly costs.

Mold InsertPolymer

Heat and applyforce

Cool and de-mold

Jenoptik Hex-03

Embossing tool selected for performanceand flexibility:

• Design

• Software

• Capabilities:• Large substrates (up to 150mmdiameter)• High Force (200kN)• High Temperature (500 degreesCelsius)

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Results

www.mems-exchange.org

SEMs of OICW S&A embossed parts

Material: PolycarbonateDepth: 280umMinimum feature resolved: in the nanometer range (surface textures transfer)Aspect ratio: 14 to 1 (20um x 20um freestanding pillars resolved 280um tall).

LIGA Mold Inserts

Currently using mold inserts fabricated using LIGA technology:

Benefits:

Excellent feature resolution

Vertical smooth sidewalls

Tapered profiles possible

Disadvantages:

Cost

Lead Time

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Alternative Mold Inserts

Machined mold inserts:

•Fine geometries possible, butnot closely spaced due to tooldiameters

•Good selection of substratematerials.

•Excellent cost and turnaround

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Accessibility

www.mems-exchange.org703-262-5368

wbenard@mems-exchange.org

•Turn-key hot embossing services

•Prototyping through production